Pulsed laser deposition of KNN-based ferroelectric thin films on platinised Si substrates

In this paper we report work on a modified potassium sodium niobate composition that has the potential to replace PZT for piezoelectric thin film applications. Pulsed laser depositions were undertaken on platinised Si substrates. The resultant films were found to be well-oriented in the [100] direction and almost phase-pure. TEM analysis of film cross-sections revealed the grain structure to be highly columnar. Values for P-s = 3.8 mu C/cm(2) and E-c = 20 kV/cm were derived from polarisation hysteresis measurements for a 32 mu m thick film. Finally, piezoresponse force microscopy was used to map the local piezoelectric activity down to the level of individual grains in the film.